For the sealing between blind frame and wing frame in windows, door wings or the like, sealing profiles or molding running around the entire inner surface of the frames are required. To obtain complete sealing, care must be taken that the allround sealing profile is closed in itself, i.e. that the profile ends facing one another are actually joined with one another. To that end, the ends of the continuous profiles facing one another in the corner areas are mitered in such a way that the miter joints of profiles arriving from different directions lie perfectly against each other and can then be glued together, welded together where the profiles of plastic, or in the case of rubber profiles, vulcanized together.
To make such corner joints of sealing profiles by welding together the ends of the profile, it has been necessary up till now to first cut the ends of the continuous sections in a cutting or punching means to produce the desired degree of miter and then in a separate procedure weld together the ends of the thus cut or punched continuous sections in a suitable welding device. In many cases, it has been found difficult to achieve a perfect joint of the sealing profiles in the corner areas of the frame, the occurrence of slit places, irregular joints and the like being able to reduce considerably not only the sealing effect, but also the heat and sound insulation of such seals. To avoid such difficulties, it is of utmost importance that the miters at the end locations of the profiles are made in an extremely careful and uniform manner and that furthermore the ends of such profiles are welded together under practically uniform conditions over the entire welding area. Only when these precautions and preconditions are assured can a time-consuming, expensive and labor-intensive aftertreatment of such corner joints be avoided.
A known welding device for the welding of the end places of sealing profiles, particularly with corner joints, has been described in West German DE-GM No. 79 11 997. The two profile ends mitered in a preceding operation are in this known device inserted in two profile holding means which are arranged on a base plate, on which a welding machine with a welding plate is also mounted. The two holding means are arranged at an angle relative to one another and their end areas so aligned in accordance with the miter angles at the profile end places that after insertion of the profiles the holding means which are shiftable toward each other at an angle in the longitudinal direction of the profile can so be brought against each other that the profile end places lie precisely against one another. A welding machine with a fixed plate is further provided towards which the two holding means are movable in such a way that the miter surfaces to be joined at the profile ends from both sides of the welding plate can be pressed against the latter. As a result, the corresponding end places of the two profile ends are heated to such a degree that upon moving the holding means away from the welding plate and immediate manual pressing together of the two holding means (and thus also of the heated profile end points against each other) the desired weld seam can be produced.
While this known device allows with proper operation a satisfactory welding together of the ends of sealing profiles, especially for making corner joints, the device is relatively complicated in that not only a relatively large base plate with the holding means must be movable relative to the welding blade, but also the two holding means must on their part be shiftable relative to the base place carrying them. These multiple, mutually superposed shifting movements require also increased attention on the part of the operator in order to correctly execute the required coordination of the individual movements relative to each other. Care must be taken, for example, that the holding means accommodating the two miter sections of the profile ends are not fully pushed together prior to being moved toward the welding plate, since then an insertion of the welding plate between the same for heating the end areas of the profiles would no longer be possible. The operator must thus take care that the two holding means after insertion of the profiles are shifted against one another only to such a degree as to leave sufficient space to allow upon shifting toward the stationary welding plate an insertion of the latter between the miter sections. Furthermore, the known device can be used only as welding means. The prior diagonal cutting of the profile ends to produce the desired accurate miter cut cannot be done with this known device.